AX5243 over current when switching to full TX mode

Hello,
I made a board with an AX5243, I’m using the configuration generated by AX-Radio lab but I had to port the code to a DSPic.

Everything seems fine until I turn on the Full TX mode in that case the RF output is a tone at about 18dBm and the current drawn is about 100mA. (In the picture the board is accountable for about 40/50mA)

I tried changing COEFFPOWER register but it doesn’t change the output power nor the current consumption.

If I change mode back to other mode then the current fallback to something normal.

Thanks and best regards,

@F4IHX

and the current drawn is about 100mA. (In the picture the board is accountable for about 40/50mA)
Please explain these values?

Current consumption of the AX5243 is specified in our datasheet and for the specified frequency at 868MHz with our matching network is as below:

TX at 868 MHz
7.5 mA @ 0 dBm
16 mA @ 10 dBm
48 mA @ 16 dBm

Are your measured values in range of 100mA?

I tried changing COEFFPOWER register but it doesn’t change the output power nor the current consumption.

Can you try to change Transmit power (dBm) in PHY layer in RadioLab software instead and download it on the AX5243 ?

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Hello,
I made many test with AxRadioLab, my own code and “NotBlackMagicCode”, the conclusion is that I have about 10dB more on the output than the configured TX Power, obvisouly at some point it saturate the amplifier output.

I’m using the chip at 144MHz with the 169MHz load network, do you think it could explain that ?

Thanks a lot,

Ok you can ignore that issue !
I stupidly connected VDD_ANA to the 3.3V !
Removed the connection and now I’m right in spec :slight_smile: